Buggy code:
public class APIImpl implements API { private static DatabaseConnector db = DatabaseConnector . getInstance ( ) ; private Map < Integer , ConfigurationScenario > csCache = new HashMap < Integer , ConfigurationScenario > ( ) ; private Map < Integer , ParameterGraph > pgCache = new HashMap < Integer , ParameterGraph > ( ) ; private Map < Integer , SolverBinaries > sbCache = new HashMap < Integer , SolverBinaries > ( ) ; public synchronized boolean connect ( String hostname , int port , String database , String username , String password ) throws Exception { <START_BUG> return connect ( hostname , port , username , database , password , false ) ; <END_BUG> } public synchronized boolean connect ( String hostname , int port , String database , String username , String password , boolean compress ) throws Exception { } public synchronized void disconnect ( ) { } public synchronized String getCanonicalName ( int idExperiment , ParameterConfiguration config ) throws Exception { } public synchronized int createSolverConfig ( int idExperiment , ParameterConfiguration config , String name ) throws Exception { } public synchronized List < Integer > createSolverConfigs ( int idExperiment , List < ParameterConfiguration > configs , List < String > names ) throws Exception { } private synchronized String calculateParameterConfigHash ( int idExperiment , ParameterConfiguration config ) throws Exception { } private synchronized List < ParameterInstance > createParameterInstancesList ( int idExperiment , SolverConfiguration solver_config , ParameterConfiguration config ) throws Exception { } public synchronized int launchJob ( int idExperiment , int idSolverConfig , int idInstance , BigInteger seed , int cpuTimeLimit ) throws Exception { } public synchronized int launchJob ( int idExperiment , int idSolverConfig , int idInstance , BigInteger seed , int cpuTimeLimit , int priority ) throws Exception { } private synchronized void extendCourse ( ConfigurationScenario cs , Random rng ) throws Exception { } public synchronized int launchJob ( int idExperiment , int idSolverConfig , int cpuTimeLimit , Random rng ) throws Exception { } public synchronized int launchJob ( int idExperiment , int idSolverConfig , int cpuTimeLimit , int priority , Random rng ) throws Exception { } public int getCourseLength ( int idExperiment ) throws Exception { } public synchronized List < Integer > launchJob ( int idExperiment , int idSolverConfig , int [ ] cpuTimeLimit , int numberRuns , Random rng ) throws Exception { } public synchronized List < Integer > launchJob ( int idExperiment , int idSolverConfig , int [ ] cpuTimeLimit , int numberRuns , int [ ] priority , Random rng ) throws Exception { } public synchronized ParameterConfiguration getParameterConfiguration ( int idExperiment , int idSolverConfig ) throws Exception { } public synchronized int exists ( int idExperiment , ParameterConfiguration config ) throws Exception { } public synchronized int getNumJobs ( int idSolverConfig ) throws Exception { } public synchronized void updateSolverConfigurationCost ( int idSolverConfig , float cost , CostFunction func ) throws Exception { } public synchronized CostFunction getCostFunction ( int idSolverConfig ) throws Exception { } public synchronized Float getSolverConfigurationCost ( int idSolverConfig ) throws Exception { } public synchronized ExperimentResult getJob ( int idJob ) throws Exception { } public synchronized ExperimentResult killJob ( int idJob ) throws Exception { } public void restartJob ( int idJob , int CPUTimeLimit ) throws Exception { } public synchronized boolean deleteResult ( int idJob ) throws Exception { } public synchronized ArrayList < ExperimentResult > getRuns ( int idExperiment , int idSolverConfig ) throws Exception { } public synchronized Map < Integer , ExperimentResult > getJobsByIDs ( List < Integer > ids ) throws Exception { } public synchronized List < Instance > getExperimentInstances ( int idExperiment ) throws Exception { } public synchronized String getSolverConfigName ( int idSolverConfig ) throws Exception { } public synchronized int getBestConfiguration ( int idExperiment , CostFunction func ) throws Exception { } public List < Integer > getBestConfigurations ( int idExperiment , CostFunction func , int no ) throws Exception { } public synchronized ParameterGraph loadParameterGraphFromDB ( int idExperiment ) throws Exception { } public synchronized ParameterGraph loadParameterGraphFromFile ( String xmlFileName ) throws Exception { } @ SuppressWarnings ( "unchecked" ) private < T > T unmarshal ( Class < T > docClass , InputStream inputStream ) throws JAXBException { } private synchronized int getCurrentMaxRun ( int idSolverConfig , int idInstance ) throws Exception { } public String toHex ( byte [ ] bytes ) { } public CostFunction costFunctionByName ( String databaseRepresentation ) { } public void updateSolverConfigurationName ( int idSolverConfig , String name ) throws Exception { } @ Override public void removeSolverConfig ( int idSolverConfig ) throws Exception { } @ Override public int getComputationCoreCount ( int idExperiment ) throws Exception { } @ Override public int getComputationJobCount ( int idExperiment ) throws Exception { } @ Override public void setJobPriority ( int idJob , int priority ) throws Exception { } @ Override public List < Integer > getSolverConfigurations ( int idExperiment ) throws Exception { } @ Override public List < Integer > getSolverConfigurations ( int idExperiment , String hint ) throws Exception { } @ Override public void setSolverConfigurationHint ( int idExperiment , int idSolverConfig , String hint ) throws Exception { } private synchronized ConfigurationScenario getConfigScenario ( int idExperiment ) throws Exception { } private synchronized ParameterGraph getParamGraph ( int idExperiment ) throws Exception { } private synchronized SolverBinaries getSolverBinary ( int idSolverBinary ) throws Exception { } public float getTotalCPUTime ( int idExperiment ) throws Exception { } @ Override public Course getCourse ( int idExperiment ) throws Exception { } }

Fix:
return connect ( hostname , port , database , username , password , false ) ;